Field of the Invention
The invention relates in general to a receiving circuit capable of estimating frequency offset and an associated method, and more particularly to a receiving circuit for estimating frequency offset under multipath interference and an associated method.
Description of the Related Art
Receiving remote signals is one of the most common functions in a modern information device. To receive a wireless or wired remote signal from a remote transmitting circuit, an information device is provided with a receiving circuit. The transmitting circuit converts and modulates a baseband signal to a radio-frequency (RF) transmitting signal according to a local frequency at the transmitting circuit, and transmits and propagates the RF transmitting signal. The transmitting signal is propagated to the receiving circuit and becomes an RF remote signal that is then received by the receiving circuit. The receiving circuit down-converts and demodulates the remote signal to recover the baseband signal.
However, due to mismatch between the local frequency at the transmitting circuit and the local frequency at the receiving circuit, a difference, i.e., a frequency offset, is present between the two. Thus, the transmitting circuit needs to estimate the frequency offset in order to correctly perform the down-conversion and signal recovery. Further, the transmitting signal may encounter various kinds of propagation interference when being propagated to the receiving circuit, including multipath interference. Propagation interference affects the estimation of frequency offset and causes an error in the estimation.